As this is your first post, welcome to the Pure Planet community!
I can understand your confusion, and on the face of it your email from Pure Planet was not all that helpful. This thread makes clear that at the moment you can't see your full statements on the app. What you can see is a summary of your usage and your payments, so in a sense all the info from your statements is available on the app.
And even if you have deleted your emailed statements, you might be able to trace them in your trash file or on the server, unless you are a very diligent email cleaner!
I just download mine to a Dropbox folder so I know I can always find them if necessary.
Does that help at all?